1. Field of the Invention
The present invention relates to a battery fitting device for use with electronic appliances and more particularly to a device for fitting a button-shaped battery to an electronic appliance such as a telephone or the like.
2. Description of the Prior Art
A conventional electronic appliance with a button-shaped battery incorporated therein is generally constructed such that a recess having the square cross-sectional configuration adapted to be fitted with a cover is formed on the side wall of the appliance. Moreover, a circular cavity or cavities for accommodating a button-shaped battery or batteries therein are formed on the bottom of the recess. One end part of a contact spring serving as a negative electrode and one end part of a contact spring serving as a positive electrode are exposed to the inner space in the circular cavity. Specifically, the end part of the negative electrode contact spring extends along the bottom surface of the circular cavity until it reaches the center of the cavity and it is then bent upwardly away from the bottom surface of the cavity. On the other hand, the end part of the positive electrode contact spring extends along the side wall of the circular cavity until its extreme end reaches the position located approximately at the middle of the height of the side wall. Both the other end parts of the negative and positive electrode contact springs are electrically connected to electronic components in the case by lead wires or the like.
After the button-shaped battery is accommodated in the circular cavity, the circular cavity is fitted with the cover and the assembly is then fitted into the square recess. Thus, fitting of the button-shaped battery to the electronic appliance is completed. The button-shaped battery firmly set in the electronic appliance in this way is used in such a manner that the seal cover (serving as a negative electrode) comes in contact with the foremost end of the negative electrode contact spring and the peripheral wall (serving as plus electrode) comes in contact with the foremost end of the positive electrode spring.
In the case of the conventional battery fitting device it is necessary to immovably hold the cover on the case of the electronic appliance. To eliminate the above-mentioned necessity, it is known to provide a projection at the one end of the cover and an additional recess formed on the side wall of the square recess, whereby fastening of the cover to the case of the electronic appliance is achieved by fitting the projection at the one end of the cover into the additional recess and then attaching the other end of the cover to the bottom surface of the square recess by means of a plurality of set screws.
However, it has been found with respect to the battery fitting device with the above-mentioned cover fastening system employed therefor that the set screws become loosened by vibration or the like, causing the cover to float up above the case, resulting in incomplete electric contact between the battery and the contact spring. Another drawback to the battery fitting device as constructed in the above-described manner is that the set screws must be removed and then replaced whenever the battery is replaced which requires a complicated handling operation. Moreover, removing the used battery is difficult due to the fact that it is fitted into the bottom of the circular cavity.